Smartphone

ABSTRACT

In one embodiment, a smartphone includes a first cover layer; an LCD panel located under the first cover layer; a backlight unit located under the LCD panel and comprising a reflective sheet and a second cover layer; and a capacitive touch sensor; wherein the backlight unit further comprises a pressure sensor and a spacer layer, the pressure sensor comprising electrodes attached on the second cover layer and spaced apart from the reflective sheet; wherein a touch position is detected by a sensing signal output from the touch sensor; wherein a magnitude of a touch pressure is detected based on a change amount of capacitance that is changed according to a distance between the pressure sensor and an electrode located within the LCD panel; wherein the LCD panel is bent according to the touch; and wherein the capacitance change amount changes as the LCD panel bends.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/820,942, filed Aug. 7, 2015, which claims priority under 35U.S.C. §119 to Korean Patent Application No. 10-2015-0105690, filed Jul.27, 2015. The disclosures of these references are incorporated herein byreference in their entireties.

FIELD OF THE INVENTION

This disclosure relates to a smartphone, and more particularly to asmartphone configured to detect a touch position and/or touch pressurein a display module.

BACKGROUND OF THE INVENTION

Various kinds of input devices are being used to operate a computingsystem. For example, the input device includes a button, key, joystickand touch screen. Since the touch screen is easy and simple to operate,the touch screen is increasingly being used in operation of thecomputing system.

The touch screen may constitute a touch surface of a touch input deviceincluding a touch sensor panel which may be a transparent panelincluding a touch-sensitive surface. The touch sensor panel is attachedto the front side of a display screen, and then the touch-sensitivesurface may cover the visible side of the display screen. The touchscreen allows a user to operate the computing system by simply touchingthe touch screen by a finger, etc. Generally, the computing systemrecognizes the touch and the touch position on the touch screen andanalyzes the touch, and thus, performs the operations in accordance withthe analysis.

Here, there is a demand for a touch input device capable of detectingnot only the touch position according to the touch on the touch screenbut the magnitude of the touch pressure without degrading theperformance of the display module.

SUMMARY OF THE INVENTION

In one embodiment, the present disclosure is directed to a smartphoneincluding a first cover layer; an LCD panel located under the firstcover layer and comprising a liquid crystal layer, a first glass layer,and a second glass layer, the liquid crystal layer located between thefirst glass layer and the second glass layer; a backlight unit locatedunder the LCD panel and comprising an optical film, a light source, areflective sheet, and a second cover layer; and a touch sensor whichsenses touch in a capacitive manner; wherein the backlight unit furthercomprises a pressure sensor and a spacer layer, the pressure sensorcomprising a plurality of electrodes formed in a single layer attachedon the second cover layer and spaced apart from the reflective sheet,the pressure sensor located between the reflective sheet and the secondcover layer; wherein a driving signal is applied to the touch sensor anda touch position is detected by a sensing signal output from the touchsensor; wherein a magnitude of a touch pressure is detected based on achange amount of capacitance that is output from the pressure sensor andthat is changed according to a distance between the pressure sensor andan electrode located within the LCD panel; wherein the LCD panel is bentaccording to the touch; and wherein the change amount of the capacitanceoutput from the pressure sensor changes as the LCD panel bends.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a configuration of a capacitance typetouch sensor panel and the operation thereof in accordance with anembodiment of the present invention;

FIGS. 2a to 2e are conceptual views showing a relative position of thetouch sensor panel with respect to a display panel in a touch inputdevice according to the embodiment of the present invention;

FIG. 3 is a cross sectional view of the touch input device configured todetect the touch position and touch pressure in accordance with theembodiment of the present invention;

FIG. 4 shows an optical layer of a backlight unit in the touch inputdevice according to the embodiment of the present invention;

FIG. 5a shows a relative distance between a pressure sensor and areference potential layer of a first example included in the touch inputdevice shown in FIG. 3;

FIG. 5b shows a case where a pressure has been applied in the structureof FIG. 5 a;

FIG. 5c shows a relative distance between a pressure sensor and areference potential layer of a second example included in the touchinput device shown in FIG. 3;

FIG. 5d shows a case where a pressure has been applied in the structureof FIG. 5 c;

FIGS. 6a to 6e show patterns according to a first to fifth examples ofan electrode constituting the pressure sensor according to theembodiment of the present invention; and

FIG. 7 shows an attachment structure of the pressure sensor according tothe embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description of the present invention shows aspecified embodiment of the present invention and will be provided withreference to the accompanying drawings. The embodiment will be describedin enough detail that those skilled in the art are able to embody thepresent invention. It should be understood that various embodiments ofthe present invention are different from each other and need not bemutually exclusive. For example, a specific shape, structure andproperties, which are described in this disclosure, may be implementedin other embodiments without departing from the spirit and scope of thepresent invention with respect to one embodiment. Also, it should benoted that positions or placements of individual components within eachdisclosed embodiment may be changed without departing from the spiritand scope of the present invention. Therefore, the following detaileddescription is not intended to be limited. If adequately described, thescope of the present invention is limited only by the appended claims ofthe present invention as well as all equivalents thereto. Similarreference numerals in the drawings designate the same or similarfunctions in many aspects.

A touch input device according to an embodiment of the present inventionwill be described with reference to the accompanying drawings. While acapacitance type touch sensor panel 100 and a pressure sensor 450 and460 are described below, another method according to the embodiment maybe applied to detect a touch position and/or a touch pressure.

FIG. 1 is a schematic view of a configuration of the capacitance touchsensor panel 100 and the operation thereof in accordance with theembodiment of the present invention. Referring to FIG. 1, the touchsensor panel 100 according to the embodiment of the present inventionmay include a plurality of drive electrodes TX1 to TXn and a pluralityof receiving electrodes RX1 to RXm, and may include a drive unit 120which applies a driving signal to the plurality of drive electrodes TX1to TXn for the purpose of the operation of the touch sensor panel 100,and a sensing unit 110 which detects whether the touch has occurred ornot and/or the touch position by receiving a sensing signal includinginformation on the capacitance change amount changing according to thetouch on the touch surface of the touch sensor panel 100.

As shown in FIG. 1, the touch sensor panel 100 may include the pluralityof drive electrodes TX1 to TXn and the plurality of receiving electrodesRX1 to RXm. While FIG. 1 shows that the plurality of drive electrodesTX1 to TXn and the plurality of receiving electrodes RX1 to RXm of thetouch sensor panel 100 form an orthogonal array, the present inventionis not limited to this. The plurality of drive electrodes TX1 to TXn andthe plurality of receiving electrodes RX1 to RXm has an array ofarbitrary dimension, for example, a diagonal array, a concentric array,a 3-dimensional random array, etc., and an array obtained by theapplication of them. Here, “n” and “m” are positive integers and may bethe same as each other or may have different values. The magnitude ofthe value may be changed depending on the embodiment.

As shown in FIG. 1, the plurality of drive electrodes TX1 to TXn and theplurality of receiving electrodes RX1 to RXm may be arranged to crosseach other. The drive electrode TX may include the plurality of driveelectrodes TX1 to TXn extending in a first axial direction. Thereceiving electrode RX may include the plurality of receiving electrodesRX1 to RXm extending in a second axial direction crossing the firstaxial direction.

In the touch sensor panel 100 according to the embodiment of the presentinvention, the plurality of drive electrodes TX1 to TXn and theplurality of receiving electrodes RX1 to RXm may be formed in the samelayer. For example, the plurality of drive electrodes TX1 to TXn and theplurality of receiving electrodes RX1 to RXm may be formed on the sameside of an insulation layer (not shown). Also, the plurality of driveelectrodes TX1 to TXn and the plurality of receiving electrodes RX1 toRXm may be formed in the different layers. For example, the plurality ofdrive electrodes TX1 to TXn and the plurality of receiving electrodesRX1 to RXm may be formed on both sides of one insulation layer (notshown) respectively, or the plurality of drive electrodes TX1 to TXn maybe formed on a side of a first insulation layer (not shown) and theplurality of receiving electrodes RX1 to RXm may be formed on a side ofa second insulation layer (not shown) different from the firstinsulation layer.

The plurality of drive electrodes TX1 to TXn and the plurality ofreceiving electrodes RX1 to RXm may be made of a transparent conductivematerial (for example, indium tin oxide (ITO) or antimony tin oxide(ATO) which is made of tin oxide (SnO₂), and indium oxide (In₂O₃),etc.), or the like. However, this is only an example. The driveelectrode TX and the receiving electrode RX may be also made of anothertransparent conductive material or an opaque conductive material. Forinstance, the drive electrode TX and the receiving electrode RX may beformed to include at least any one of silver ink, copper or carbonnanotube (CNT). Also, the drive electrode TX and the receiving electrodeRX may be made of metal mesh or nano silver.

The drive unit 120 according to the embodiment of the present inventionmay apply a driving signal to the drive electrodes TX1 to TXn. In theembodiment of the present invention, one driving signal may besequentially applied at a time to the first drive electrode TX1 to then-th drive electrode TXn. The driving signal may be applied againrepeatedly. This is only an example. The driving signal may be appliedto the plurality of drive electrodes at the same time in accordance withthe embodiment.

Through the receiving electrodes RX1 to RXm, the sensing unit 110receives the sensing signal including information on a capacitance (Cm)101 generated between the receiving electrodes RX1 to RXm and the driveelectrodes TX1 to TXn to which the driving signal has been applied,thereby detecting whether or not the touch has occurred and where thetouch has occurred. For example, the sensing signal may be a signalcoupled by the capacitance (CM) 101 generated between the receivingelectrode RX and the drive electrode TX to which the driving signal hasbeen applied. As such, the process of sensing the driving signal appliedfrom the first drive electrode TX1 to the n-th drive electrode TXnthrough the receiving electrodes RX1 to RXm can be referred to as aprocess of scanning the touch sensor panel 100.

For example, the sensing unit 110 may include a receiver (not shown)which is connected to each of the receiving electrodes RX1 to RXmthrough a switch. The switch becomes the on-state in a time intervalduring which the signal of the corresponding receiving electrode RX issensed, thereby allowing the receiver to sense the sensing signal fromthe receiving electrode RX. The receiver may include an amplifier (notshown) and a feedback capacitor coupled between the negative (−) inputterminal of the amplifier and the output terminal of the amplifier,i.e., coupled to a feedback path. Here, the positive (+) input terminalof the amplifier may be connected to the ground or a reference voltage.Also, the receiver may further include a reset switch which is connectedin parallel with the feedback capacitor. The reset switch may reset theconversion from current to voltage that is performed by the receiver.The negative input terminal of the amplifier is connected to thecorresponding receiving electrode RX and receives and integrates acurrent signal including information on the capacitance (CM) 101, andthen converts the integrated current signal into voltage. The sensingunit 110 may further include an analog to digital converter (ADC) (notshown) which converts the integrated data by the receiver into digitaldata. Later, the digital data may be input to a processor (not shown)and processed to obtain information on the touch on the touch sensorpanel 100. The sensing unit 110 may include the ADC and processor aswell as the receiver.

A controller 130 may perform a function of controlling the operations ofthe drive unit 120 and the sensing unit 110. For example, the controller130 generates and transmits a drive control signal to the drive unit120, so that the driving signal can be applied to a predetermined driveelectrode TX1 at a predetermined time. Also, the controller 130generates and transmits the drive control signal to the sensing unit110, so that the sensing unit 110 may receive the sensing signal fromthe predetermined receiving electrode RX at a predetermined time andperform a predetermined function.

In FIG. 1, the drive unit 120 and the sensing unit 110 may constitute atouch detection device (not shown) capable of detecting whether thetouch has occurred on the touch sensor panel 100 according to theembodiment of the present invention or not and/or where the touch hasoccurred. The touch detection device according to the embodiment of thepresent invention may further include the controller 130. The touchdetection device according to the embodiment of the present inventionmay be integrated and implemented on a touch sensing integrated circuit(IC, not shown) in a touch input device 1000 including the touch sensorpanel 100. The drive electrode TX and the receiving electrode RXincluded in the touch sensor panel 100 may be connected to the driveunit 120 and the sensing unit 110 included in the touch sensing ICthrough, for example, a conductive trace and/or a conductive patternprinted on a circuit board, or the like. The touch sensing IC may belocated on a circuit board on which the conductive pattern has beenprinted. According to the embodiment, the touch sensing IC may bemounted on a main board for operation of the touch input device 1000.

As described above, a capacitance (C) with a predetermined value isgenerated at each crossing of the drive electrode TX and the receivingelectrode RX. When an object like a finger approaches close to the touchsensor panel 100, the value of the capacitance may be changed. In FIG.1, the capacitance may represent a mutual capacitance (Cm). The sensingunit 110 senses such electrical characteristics, thereby being able tosense whether the touch has occurred on the touch sensor panel 100 ornot and where the touch has occurred. For example, the sensing unit 110is able to sense whether the touch has occurred on the surface of thetouch sensor panel 100 comprised of a two-dimensional plane consistingof a first axis and a second axis.

More specifically, when the touch occurs on the touch sensor panel 100,the drive electrode TX to which the driving signal has been applied isdetected, so that the position of the second axial direction of thetouch can be detected. Likewise, when the touch occurs on the touchsensor panel 100, the capacitance change is detected from the receptionsignal received through the receiving electrode RX, so that the positionof the first axial direction of the touch can be detected.

The mutual capacitance type touch sensor panel as the touch sensor panel100 has been described in detail in the foregoing. However, in the touchinput device 1000 according to the embodiment of the present invention,the touch sensor panel 100 for detecting whether or not the touch hasoccurred and where the touch has occurred may be implemented by usingnot only the above-described method but also any touch sensing methodlike a self-capacitance type method, a surface capacitance type method,a projected capacitance type method, a resistance film method, a surfaceacoustic wave (SAW) method, an infrared method, an optical imagingmethod, a dispersive signal technology, and an acoustic pulserecognition method, etc.

Here, the configuration including the drive electrode TX and thereceiving electrode RX for detecting whether or not the touch hasoccurred and/or the touch position can be referred to as a touch sensor.

The touch sensor panel 100 for detecting where the touch has occurred inthe touch input device 1000 according to the embodiment of the presentinvention may be positioned outside or inside a display panel 200.

The display panel 200 of the touch input device 1000 according to theembodiment of the present invention may be a display panel included in aliquid crystal display (LCD), a plasma display panel (PDP), an organiclight emitting diode (OLED), etc. Accordingly, a user may perform theinput operation by touching the touch surface while visually identifyingan image displayed on the display panel. Here, the display panel 200 mayinclude a control circuit which receives an input from an applicationprocessor (AP) or a central processing unit (CPU) on a main board forthe operation of the touch input device 1000 and displays the contentsthat the user wants on the display panel. Here, the control circuit forthe operation of the display panel 200 may include a display panelcontrol IC, a graphic controller IC, and a circuit required to operateother display panels 200.

FIGS. 2a to 2e are conceptual views showing a relative position of thetouch sensor panel 100 with respect to a display panel 200 in the touchinput device according to the embodiment of the present invention.

First, a relative position of the touch sensor panel 100 with respect tothe display panel 200 using an LCD panel will be described withreference to FIGS. 2a to 2 c.

As shown in FIGS. 2a to 2c , the LCD panel may include a liquid crystallayer 250 including a liquid crystal cell, a first glass layer 261 and asecond glass layer 262 which are disposed on both sides of the liquidcrystal layer 250 and include electrodes, a first polarizer layer 271formed on a side of the first glass layer 261 in a direction facing theliquid crystal layer 250, and a second polarizer layer 272 formed on aside of the second glass layer 262 in the direction facing the liquidcrystal layer 250. Here, the first glass layer 261 may be a color filterglass, and the second glass layer 262 may be a TFT glass.

It is clear to those skilled in the art that the LCD panel may furtherinclude other configurations for the purpose of performing thedisplaying function and may be transformed.

FIG. 2a shows that the touch sensor panel 100 of the touch input device1000 is disposed outside the display panel 200. The touch surface of thetouch input device 1000 may be the surface of the touch sensor panel100. In FIG. 2a , the top surface of the touch sensor panel 100 is ableto function as the touch surface. Also, according to the embodiment, thetouch surface of the touch input device 1000 may be the outer surface ofthe display panel 200. In FIG. 2a , the bottom surface of the secondpolarizer layer 272 of the display panel 200 is able to function as thetouch surface. Here, in order to protect the display panel 200, thebottom surface of the display panel 200 may be covered with a coverlayer (not shown) like glass.

FIGS. 2b and 2c show that the touch sensor panel 100 of the touch inputdevice 1000 is disposed inside the display panel 200. Here, in FIG. 2b ,the touch sensor panel 100 for detecting the touch position is disposedbetween the first glass layer 261 and the first polarizer layer 271.Here, the touch surface of the touch input device 1000 is the outersurface of the display panel 200. The top surface or bottom surface ofthe display panel 200 in FIG. 2b may be the touch surface. FIG. 2c showsthat the touch sensor panel 100 for detecting the touch position isincluded in the liquid crystal layer 250. Here, the touch surface of thetouch input device 1000 is the outer surface of the display panel 200.The top surface or bottom surface of the display panel 200 in FIG. 2cmay be the touch surface. In FIGS. 2b and 2c , the top surface or bottomsurface of the display panel 200, which can be the touch surface, may becovered with a cover layer (not shown) like glass.

Next, a relative position of the touch sensor panel 100 with respect tothe display panel 200 using an OLED panel will be described withreference to FIGS. 2d and 2e . In FIG. 2d , the touch sensor panel 100is located between a polarizer layer 282 and a first glass layer 281. InFIG. 2e , the touch sensor panel 100 is located between an organic layer280 and a second glass layer 283.

Here, the first glass layer 281 may be comprised of an encapsulationglass, and the second glass layer 283 may be comprised of a TFT glass.Since the touch sensing has been described above, only the otherconfigurations thereof will be briefly described.

The OLED panel is a self-light emitting display panel which uses aprinciple in which current flows through a fluorescent or phosphorescentorganic thin film and then electrons and electron holes are combined inthe organic layer, so that light is generated. The organic matterconstituting the light emitting layer determines the color of the light.

Specifically, the OLED uses a principle in which when electricity flowsand an organic matter is applied on glass or plastic, the organic matteremits light. That is, the principle is that electron holes and electronsare injected into the anode and cathode of the organic matterrespectively and are recombined in the light emitting layer, so that ahigh energy exciton is generated and the exciton releases the energywhile falling down to a low energy state and then light with aparticular wavelength is generated. Here, the color of the light ischanged according to the organic matter of the light emitting layer.

The OLED includes a line-driven passive-matrix organic light-emittingdiode (PM-OLED) and an individual driven active-matrix organiclight-emitting diode (AM-OLED) in accordance with the operatingcharacteristics of a pixel constituting a pixel matrix. None of themrequire a backlight. Therefore, the OLED enables a very thin displaypanel to be implemented, has a constant contrast ratio according to anangle and obtains a good color reproductivity depending on atemperature. Also, it is very economical in that non-driven pixel doesnot consume power.

In terms of operation, the PM-OLED emits light only during a scanningtime at a high current, and the AM-OLED maintains a light emitting stateonly during a frame time at a low current. Therefore, the AM-OLED has aresolution higher than that of the PM-OLED and is advantageous fordriving a large area display panel and consumes low power. Also, a thinfilm transistor (TFT) is embedded in the AM-OLED, and thus, eachcomponent can be individually controlled, so that it is easy toimplement a delicate screen.

As shown in FIGS. 2d and 2e , basically, the OLED (particularly,AM-OLED) panel includes the polarizer layer 282, the first glass layer281, the organic layer 280, and the second glass layer 283. Here, thefirst glass layer 281 may be a cover glass and the second glass layer283 may be a TFT glass. However, they are not limited to this.

Also, the organic layer 280 may include a hole injection layer (HIL), ahole transport layer (HTL), an electron injection layer (EIL), anelectron transport layer (ETL), and a light-emitting layer (EML).

Briefly describing each of the layers, HIL injects electron holes anduses a material such as CuPc, etc. HTL functions to move the injectedelectron holes and mainly uses a material having a good hole mobility.Arylamine, TPD, and the like may be used as the HTL. The EIL and ETLinject and transport electrons. The injected electrons and electronholes are combined in the EML and emit light. The EML represents thecolor of the emitted light and is composed of a host determining thelifespan of the organic matter and an impurity (dopant) determining thecolor sense and efficiency. This just describes the basic structure ofthe organic layer 280 include in the OLED panel. The present inventionis not limited to the layer structure or material, etc., of the organiclayer 280.

The organic layer 280 is inserted between the anode (not shown) and acathode (not shown). When the TFT becomes an on-state, a driving currentis applied to the anode and the electron holes are injected, and theelectrons are injected to the cathode. Then, the electron holes andelectrons move to the organic layer 280 and emit the light.

Also, according to the embodiment, at least a portion of the touchsensor may be configured to be positioned within the display panel 200,and at least a portion of the remaining touch sensor may be configuredto be positioned outside the display panel 200. For example, any one ofthe drive electrode TX and the receiving electrode RX which constitutethe touch sensor panel 100 may be configured to be positioned outsidethe display panel 200, the remaining electrode may be configured to bepositioned within the display panel 200. When the touch sensor isdisposed within the display panel 200, an electrode for operating thetouch sensor may be further disposed. However, various configurationsand/or the electrode which are located within the display panel 200 maybe used as the touch sensor for touch sensing.

The second glass layer 262 may be comprised of various layers includinga data line a gate line, TFT, a common electrode, and a pixel electrode,etc. These electrical components may operate in such a manner as togenerate a controlled electric field and orient liquid crystals locatedin the liquid crystal layer 250. Any one of the data line, gate line,common electrode, and pixel electrode included in the second glass layer262 may be configured to be used as the touch sensor.

Up to now, the touch position detection by the touch sensor panel 100according to the embodiment of the present invention has been described.Additionally, through use of the touch sensor panel 100 according to theembodiment of the present invention, it is possible to detect themagnitude of the touch pressure as well as whether the touch hasoccurred or not and/or where the touch has occurred. Also, a pressuresensor for detecting the touch pressure is included separately from thetouch sensor panel 100, so that it is possible to detect the magnitudeof the touch pressure. Hereafter, the pressure sensor and the touchinput device including the same will be described in detail.

FIG. 3 is a cross sectional view of the touch input device configured todetect the touch position and touch pressure in accordance with theembodiment of the present invention. As shown in FIG. 3, the touch inputdevice 1000 according to the embodiment of the present invention mayinclude the display panel 200, a backlight unit 300 disposed under thedisplay panel 200, and a cover layer 500 disposed on the display panel200. In the touch input device 1000 according to the embodiment of thepresent invention, the pressure sensor 450 and 460 may be formed on acover 340. In this specification, the display panel 200 and thebacklight unit 300 may be collectively referred to as a display module.In this specification, though it is shown that the pressure sensor 450and 460 are attached on the cover 340, the pressure sensor 450 and 460can be attached to a configuration which is included in the touch inputdevice 1000 and performs the same and/or similar function as/to that ofthe cover 340 in accordance with the embodiment.

The touch input device 1000 according to the embodiment of the presentinvention may include an electronic device including the touch screen,for example, a cell phone, a personal data assistant (PDA), a smartphone, a tablet personal computer, an MP3 player, a laptop computer,etc.

In the touch input device 1000 according to the embodiment of thepresent invention, at least a portion of the touch sensor may beincluded within the display panel 200. Also, the drive electrode and thereceiving electrodes for touch sensing may be included within thedisplay panel 200 in accordance with the embodiment.

The cover layer 500 according to the embodiment of the present inventionmay be comprised of a cover glass which protects the front surface ofthe display panel 200 and forms the touch surface. As shown in FIG. 3,the cover layer 500 may be formed wider than the display panel 200.

Since the display panel 200 such as the LCD panel according to theembodiment of the present invention performs a function of only blockingor transmitting the light without emitting light by itself, thebacklight unit 300 may be required. For example, the backlight unit 300is disposed under the display panel 200, includes a light source andthrows the light on the display panel 200, so that not only brightnessand darkness but also information having a variety of colors isdisplayed on the screen. Since the display panel 200 is a passivedevice, it is not self-luminous. Therefore, the rear side of the displaypanel 200 requires a light source having a uniform luminancedistribution.

The backlight unit 300 according to the embodiment of the presentinvention may include an optical layer 320 for illuminating the displaypanel 200. The optical layer 320 will be described in detail withreference to FIG. 4.

The backlight unit 300 according to the embodiment of the presentinvention may include the cover 340. The cover 340 may be made of ametallic material. When a pressure is applied from the outside throughthe cover layer 500 of the touch input device 1000, the cover layer 500and the display panel 200 may be bent. Here, the bending causes adistance between the pressure sensor 450 and 460 and a referencepotential layer located within the display module to be changed. Thecapacitance change caused by the distance change is detected through thepressure sensor 450 and 460, so that the magnitude of the pressure canbe detected. Here, a pressure is applied to the cover layer 500 in orderto precisely detect the magnitude of the pressure, the position of thepressure sensor 450 and 460 needs to be fixed without changing.Therefore, the cover 340 is able to perform a function of a support partcapable of fixing a pressure sensor without being bent even by theapplication of pressure. According to the embodiment, the cover 340 ismanufactured separately from the backlight unit 300, and may beassembled together when the display module is manufactured.

In the touch input device 1000 according to the embodiment of thepresent invention, a first air gap 310 may be included between thedisplay panel 200 and the backlight unit 300. This intends to protectthe display panel 200 and/or the backlight unit 300 from an externalimpact. This first air gap 310 may be configured to be included in thebacklight unit 300.

The optical layer 320 and the cover 340, which are included in thebacklight unit 300, may be configured to be spaced apart from eachother. A second air gap 330 may be provided between the optical layer320 and the cover 340. The second air gap 330 may be required in orderto ensure that the pressure sensor 450 and 460 disposed on the cover 340does not contact with the optical layer 320, and in order to preventthat the optical layer 320 contacts with the pressure sensor 450 and460, and thus, deteriorates the performance of the optical layer 320even though an external pressure is applied to the cover layer 500 andthe optical layer 320, the display panel 200, and the cover layer 500are bent.

The touch input device 1000 according to the embodiment of the presentinvention may further include a support part 351 and 352 such that thedisplay panel 200, the backlight unit 300, and the cover layer 500 arecoupled to maintain a fixed shape. According to the embodiment, thecover 340 may be integrally formed with the support part 351 and 352.According to the embodiment, the support part 351 and 352 may form aportion of the backlight unit 300.

The structure and function of the LCD panel 200 and the backlight unit300 is a publicly known art and will be briefly described below. Thebacklight unit 300 may include several optical parts.

FIG. 4 shows the optical layer 320 of the backlight unit 300 in thetouch input device according to the embodiment of the present invention.FIG. 4 shows the optical layer 320 when the LCD panel is used as thedisplay panel 200.

In FIG. 4, the optical layer 320 of the backlight unit 300 may include areflective sheet 321, a light guide plate 322, a diffuser sheet 323, anda prism sheet 324. Here, the backlight unit 300 may include a lightsource (not shown) which is formed in the form of a linear light sourceor a point light source, etc., and is disposed on the rear and/or sideof the light guide plate 322.

The light guide plate 322 may generally convert lights from the lightsource (not shown) in the form of a linear light source or point lightsource into light from a light source in the form of a surface lightsource, and allow the light to proceed to the LCD panel 200.

A part of the light emitted from the light guide plate 322 may beemitted to a side opposite to the LCD panel 200 and be lost. Thereflective sheet 321 may be positioned below the light guide plate 322so as to cause the lost light to be incident again on the light guideplate 322, and may be made of a material having a high reflectance.

The diffuser sheet 323 functions to diffuse the light incident from thelight guide plate 322. For example, light scattered by the pattern ofthe light guide plate 322 comes directly into the eyes of the user, andthus, the pattern of the light guide plate 322 may be shown as it is.Moreover, since such a pattern can be clearly sensed even after the LCDpanel 200 is mounted, the diffuser sheet 323 is able to perform afunction to offset the pattern of the light guide plate 322.

After the light passes through the diffuser sheet 323, the luminance ofthe light is rapidly reduced. Therefore, the prism sheet 324 may beincluded in order to improve the luminance of the light by focusing thelight again. The prism sheet 324 may include a horizontal prism sheetand a vertical prism sheet.

The backlight unit 300 may include a configuration different from theabove-described configuration in accordance with the technical changeand development and/or the embodiment. The backlight unit 300 mayfurther include an additional configuration as well as the foregoingconfiguration. Also, in order to protect the optical configuration ofthe backlight unit 300 from external impacts and contamination, etc.,due to the introduction of the alien substance, the backlight unit 300according to the embodiment of the present may further include, forexample, a protection sheet on the prism sheet 324. The backlight unit300 may also further include a lamp cover in accordance with theembodiment so as to minimize the optical loss of the light source. Thebacklight unit 300 may also further include a frame which maintains ashape enabling the light guide plate 322, the diffuser sheet 323, theprism sheet 324, and a lamp (not shown), and the like, which are maincomponents of the backlight unit 300, to be exactly combined together inaccordance with an allowed dimension. Also, the each of theconfigurations may be comprised of at least two separate parts.

According to the embodiment, an additional air gap may be positionedbetween the light guide plate 322 and the reflective sheet 321. As aresult, the lost light from the light guide plate 322 to the reflectivesheet 321 can be incident again on the light guide plate 322 by thereflective sheet 321. Here, between the light guide plate 322 and thereflective sheet 321, for the purpose of maintaining the additional airgap, a double adhesive tape (DAT) may be included on the edges of thelight guide plate 322 and the reflective sheet 321.

As described above, the backlight unit 300 and the display moduleincluding the same may be configured to include in itself the air gapsuch as the first air gap 310 and/or the second air gap 330. Also, theair gap may be included between a plurality of the layers included inthe optical layer 320. In the foregoing, while the case where the LCDpanel 200 is employed has been described, the air gap may be includedwithin the structure of another display panel.

Hereafter, in the touch input device 1000 according to the embodiment ofthe present invention, the principle and structure for detecting themagnitude of touch pressure by using the pressure sensor 450 and 460will be described in detail.

FIG. 5a shows a relative distance between the pressure sensor and thereference potential layer of a first example included in the touch inputdevice shown in FIG. 3. In the touch input device 1000 according to theembodiment of the present invention, the pressure sensor 450 and 460 maybe attached on the cover 340 capable of constituting the backlight unit300. In the touch input device 1000, the pressure sensor 450 and 460 andthe reference potential layer 600 may be spaced apart from each other bya distance “d”.

In FIG. 5a , the reference potential layer 600 and the pressure sensor450 and 460 may be spaced apart from each other with a spacer layer (notshown) placed therebetween. Here, as described with reference to FIGS. 3and 4, the spacer layer may be the first air gap 310, the second air gap330, and/or an additional air gap which are included in the manufactureof the display module and/or the backlight unit 300. When the displaymodule and/or the backlight unit 300 includes one air gap, the one airgap is able to perform the function of the spacer layer. When thedisplay module and/or the backlight unit 300 includes a plurality of airgaps, the plurality of air gaps are able to collectively perform thefunction of the spacer layer.

In the touch input device 1000 according to the embodiment of thepresent invention, the spacer layer may be located between the referencepotential layer 600 and the pressure sensor 450 and 460. As a result,when a pressure is applied to the cover layer 500, the referencepotential layer 600 is bent, so that a relative distance between thereference potential layer 600 and the pressure sensor 450 and 460 may bereduced.

In the touch input device 1000 according to the embodiment of thepresent invention, the display module may be bent or pressed by thetouch applying the pressure. The display module may be bent or pressedin such a manner as to show the biggest transformation at the touchposition. When the display module is bent or pressed according to theembodiment, a position showing the biggest transformation may not matchthe touch position. However, the display module may be shown to be bentor pressed at least at the touch position. For example, when the touchposition approaches close to the border, edge, etc., of the displaymodule, the most bent or pressed position of the display module may notmatch the touch position, however, the display module may be shown to bebent or pressed at least at the touch position.

When the cover layer 500, the display module 200, and/or the back lightunit 300 are bent or pressed at the time of touching the touch inputdevice 1000 according to the embodiment, the cover 340 positioned belowthe spacer layer, as shown in FIG. 5b , may be less bent or pressed dueto the spacer layer. While FIG. 5b shows that the cover 340 is not bentor pressed at all, this is just an example. The lowest portion of thecover 340 to which the pressure sensor 450 and 460 has been attached maybe bent or pressed. However, the degree to which the lowest portion ofthe cover 340 is bent or pressed can be reduced by the spacer layer.

According to the embodiment, the spacer layer may be implemented in theform of the air gap. The spacer layer may be made of an impact absorbingmaterial in accordance with the embodiment. The spacer layer may befilled with a dielectric material in accordance with the embodiment.

FIG. 5b shows that a pressure is applied to the structure of FIG. 5a .For example, when the external pressure is applied to the cover layer500 shown in FIG. 3, it can be seen that a relative distance between thereference potential layer 600 and the pressure sensor 450 and 460 isreduced from “d” to “d′”. Accordingly, in the touch input device 1000according to the embodiment, when the external pressure is applied, thereference potential layer 600 is configured to be more bent than thecover 340 to which the pressure sensor 450 and 460 has been attached, sothat it is possible to detect the magnitude of touch pressure.

FIGS. 3, 5 a, and 5 b show that a first electrode 450 and a secondelectrode 460 are included as the pressure sensor 450 and 460 fordetecting the pressure. Here, the mutual capacitance may be generatedbetween the first electrode 450 and the second electrode 460. Here, anyone of the first and the second electrodes 450 and 460 may be a driveelectrode and the other may be a receiving electrode. A driving signalis applied to the drive electrode, and a sensing signal may be obtainedthrough the receiving electrode. When voltage is applied, the mutualcapacitance may be generated between the first electrode 450 and thesecond electrode 460.

The reference potential layer 600 have any potential which causes thechange of the mutual capacitance generated between the first electrode450 and the second electrode 460. For instance, the reference potentiallayer 600 may be a ground layer having a ground potential. The referencepotential layer 600 may be any ground layer which is included in thedisplay module. According to the embodiment, the reference potentiallayer 600 may be a ground potential layer which is included in itselfduring the manufacture of the touch input device 1000. For example, inthe display panel 200 shown in FIGS. 2a to 2c , an electrode (not shown)for blocking noise may be included between the first polarizer layer 271and the first glass layer 261. This electrode for blocking the noise maybe composed of ITO and may function as the ground. Also, according tothe embodiment, a plurality of the common electrodes included in thedisplay panel 200 constitutes the reference potential layer 600. Here,the potential of the common electrode may be a reference potential.

When a pressure is applied to the cover layer 500 by means of an object,at least a portion of the display panel 200 and/or the backlight unit300 is bent, so that a relative distance between the reference potentiallayer 600 and the first and second electrodes 450 and 460 may be reducedfrom “d” to “d′”. Here, the less the distance between the referencepotential layer 600 and the first and second electrodes 450 and 460 is,the less the value of the mutual capacitance between the first electrode450 and the second electrode 460 may be. This is because the distancebetween the reference potential layer 600 and the first and secondelectrodes 450 and 460 is reduced from “d” to “d′”, so that a fringingcapacitance of the mutual capacitance is absorbed in the referencepotential layer 600 as well as in the object. When a nonconductiveobject touches, the change of the mutual capacitance is simply caused byonly the change of the distance “d-d′” between the reference potentiallayer 600 and the electrodes 450 and 460.

FIGS. 3, 5 a, and 5 b show that the first electrode 450 and the secondelectrode 460 are formed as the pressure sensors 450 and 460 in the samelayer. However, it can be considered that the first electrode 450 andthe second electrode 460 are formed in different layers in accordancewith a process or the embodiment. A case where the first electrode 450and the second electrode 460 are formed in different layers will bedescribed in detail with reference to FIG. 7 b.

The foregoing has described that the first electrode 450 and the secondelectrode 460 are included as the pressure sensor 450 and 460, and thepressure is detected by the change of the mutual capacitance between thefirst electrode 450 and the second electrode 460. The pressure sensor450 and 460 may be configured to include only any one of the firstelectrode 450 and the second electrode 460 (for example, the firstelectrode 450).

FIG. 5c shows a relative distance between the pressure sensor and thereference potential layer of a second example included in the touchinput device shown in FIG. 3. FIG. 5d shows that a pressure is appliedto the structure of FIG. 5c . Here, it is possible to detect themagnitude of touch pressure by detecting the self-capacitance betweenthe first electrode 450 and the reference potential layer 600. Here, thechange of the self-capacitance between the first electrode 450 and thereference potential layer 600 is detected by applying the driving signalto the first electrode 450 and by receiving the reception signal fromthe first electrode 450, so that the magnitude of the touch pressure isdetected.

For example, the magnitude of the touch pressure can be detected by thechange of the capacitance between the first electrode 450 and thereference potential layer 600, which is caused by the distance changebetween the reference potential layer 600 and the first electrode 450.Since the distance “d” is reduced with the increase of the touchpressure, the capacitance between the reference potential layer 600 andthe first electrode 450 may be increased with the increase of the touchpressure.

According to the embodiment, when the magnitude of the touch pressure issufficiently large, a state may be created in which the distance betweenthe reference potential layer 600 and the pressure sensors 450 and 460is not reduced any more at a predetermined position. Hereafter, thisstate will be referred to as a saturation state. However, even in thiscase, when the magnitude of the touch pressure becomes larger, an areain the saturation state where the distance between the referencepotential layer 600 and the pressure sensors 450 and 460 is not reducedany more may become greater. The greater the area is, the more themutual capacitance between the first electrode 450 and the secondelectrode 460 may be reduced. Hereafter, it will be described that themagnitude of the touch pressure is calculated by the change of thecapacitance according to the distance change. However, this may includethat the size of the touch pressure is calculated by the change of thearea in the saturation state.

FIGS. 3 and 5 a to 5 d show that the first electrode 450 and/or thesecond electrode 460 are relatively thick and they are directly attachedto the cover 340. However, this is just only for convenience ofdescription. In accordance with the embodiment, the first electrode 450and/or the second electrode 460 may be, for example, attached to thecover 340 in the form of a sheet and may have a relatively smallthickness.

FIGS. 6a to 6e show patterns according to a first to fifth examples ofan electrode constituting the pressure sensor according to theembodiment of the present invention.

FIG. 6a shows that a pattern according to the first example of thepressure electrode when the touch pressure is detected through thechange of the mutual capacitance between the first electrode 450 and thesecond electrode 460. When the magnitude of the touch pressure isdetected as the mutual capacitance between the first electrode 450 andthe second electrode 460 is changed, it is necessary to form thepatterns of the first electrode 450 and the second electrode 460 so asto generate the range of the capacitance required to improve thedetection accuracy. With the increase of a facing area or facing lengthof the first electrode 450 and the second electrode 460, the magnitudeof the capacitance that is generated may become larger. Therefore, thepattern can be designed by adjusting the size of the facing area, facinglength and facing shape of the first electrode 450 and the secondelectrode 460 in accordance with the range of the necessary capacitance.FIG. 6a shows a pressure electrode pattern having a comb teeth shapesuch that the facing length of the first electrode 450 and the secondelectrode 460 becomes longer.

FIG. 6a shows that the first electrode 450 and the second electrode 460constitutes one channel for detecting the pressure. FIG. 6b shows apattern when the pressure sensor constitutes two channels. FIG. 6b showsthe first electrode 450-1 and the second electrode 460-1 whichconstitute a first channel, and the first electrode 450-2 and the secondelectrode 460-2 which constitute a second channel. FIG. 6c shows thatthe first electrode 450 constitutes two channels 450-1 and 450-2, andthe second electrode 460 constitutes one channel. Since the pressuresensor detects the magnitude of the touch pressure at differentpositions through the first channel and the second channel, even when amulti touch occurs, the magnitude of each touch pressure can bedetected. Here, in accordance with the embodiment, the pressure sensor450 and 460 may be configured to constitute a larger number of channels.

FIG. 6d shows an electrode pattern when the magnitude of the touchpressure is detected according to the change of the self-capacitancebetween the reference potential layer 600 and the first electrode 450.Although FIG. 6d shows a pattern having a comb teeth shape as the firstelectrode 450, the first electrode 450 may have a plate shape (forexample, a quadrangular plate shape).

FIG. 6e shows that the first electrodes 451 to 459 constitute ninechannels. That is, FIG. 6d shows that one channel is constituted, andFIG. 6e shows a pressure sensor when nine channels are constituted.Therefore, in FIG. 6e , even when a multi touch occurs, the magnitude ofeach touch pressure can be detected. Here, the pressure sensor can beconfigured to constitute another number of the channels.

FIG. 7 shows an attachment structure of the pressure sensor according tothe embodiment of the present invention. The pressure sensor 450 and 460may be attached to the cover 340 by means of an adhesive material like adouble-sided contact tape (DAT), an optically clear adhesive (OCA), andan optical clear resin (OCR), etc. Here, the pressure sensor 450 and 460may be fully laminated on the cover 340.

As shown in FIG. 7a , in order to prevent the cover 340 and the pressuresensor 450 and 460 from being short-circuited, the pressure sensor 450and 460 may be formed on an insulating layer 470. Describing withreference to FIG. 7a , the pressure sensor 450 and 460 may be disposedon the cover 340 to have the first insulating layer 470 placedtherebetween. In accordance with the embodiment, the first insulatinglayer 470 on which the pressure sensor 450 and 460 has been formed maybe attached on the cover 340. Also, in accordance with the embodiment,the pressure sensor may be formed by positioning a mask, which has athrough-hole corresponding to the pressure electrode pattern, on thefirst insulating layer 470, and then by spraying a conductive material.As shown in FIG. 7a , the pressure sensor 450 and 460 may be coveredwith an additional second insulating layer 471. Also, in accordance withthe embodiment, the pressure electrode 450 and 460 formed on the firstinsulating layer 470 is covered with the additional second insulatinglayer 471, and then are integrally attached on the cover 340. Also, inaccordance with the embodiment, the first insulating layer 470 in itselfmay be made of an adhesive material.

Also, depending on the kind and/or implementation method of the touchinput device 1000, the cover 340 on which the pressure sensor 450 and460 is attached may not have the ground potential or may have a weakground potential. In this case, the touch input device 1000 according tothe embodiment of the present may further include a ground electrode(not shown) between the cover 340 and the first insulation layer 470.According to the embodiment, another insulation layer (not shown) may beincluded between the ground electrode and the cover 340. Here, theground electrode (not shown) is able to prevent the magnitude of thecapacitance generated between the first electrode 450 and the secondelectrode 460, which are pressure sensors, from increasing excessively.

In the foregoing, the first and second embodiments show that the firstelectrode 450 and the second electrode 460 are formed in the same layer.However, it can be considered that the first electrode 450 and thesecond electrode 460 are formed in different layers in accordance withthe embodiment. It is shown in (b) of FIG. 7 that an attachmentstructure in which the first electrode 450 and the second electrode 460are formed in different layers. As shown in (b) of FIG. 7, the firstelectrode 450 may be formed on the first insulation layer 470, and thesecond electrode 460 may be formed on the second insulation layer 471positioned on the first electrode 450. According to the embodiment, thesecond electrode 460 may be covered with a third insulation layer 472.Here, since the first electrode 450 and the second electrode 460 aredisposed in different layers, they can be implemented so as to overlapeach other. For example, the first electrode 450 and the secondelectrode 460 may be formed similarly to the pattern of the driveelectrode TX and receiving electrode RX which are arranged in the formof M×N array and are included in the touch sensor panel 100 describedwith reference to FIG. 1. Here, M and N may be natural numbers greaterthan 1.

It is shown in (c) of FIG. 7 that an attachment structure in which thepressure electrode is formed to include only the first electrode 450. Asshown in (c) of FIG. 7, the first electrode 450 may be formed on thecover 340 to have the first insulation layer 470 placed therebetween.Also, according to the embodiment, the first electrode 450 may becovered with the second insulation layer 471.

In FIGS. 7a to 7c , the case where the pressure sensor constitutes onechannel has been described. However, the description of FIGS. 7a to 7ccan be applied to a case where the pressure sensor constitutes aplurality of the channels.

In accordance with the embodiment, the pressure sensor 450 and 460 isdisposed between the insulating layer 470, 471, and 472, and may beattached to the cover 340 integrally with the insulating layer in theform of an electrode sheet.

In the touch input device 1000 according to the embodiment of thepresent invention, the touch pressure can be detected by using the airgap and/or potential layer which are positioned within the display panel200 and/or the backlight unit 300 without manufacturing a separatespacer layer and/or reference potential layer.

Also, in the touch input device 1000 according to the embodiment of thepresent invention, the pressure sensor 450 and 460 and the air gap 420for detecting the pressure are disposed behind the display panel 200.Accordingly, the color clarity, visibility, and optical transmittance ofthe display panel can be improved.

Although embodiments of the present invention were described above,these are just examples and do not limit the present invention. Further,the present invention may be changed and modified in various ways,without departing from the essential features of the present invention,by those skilled in the art. For example, the components described indetail in the embodiments of the present invention may be modified.Further, differences due to the modification and application should beconstrued as being included in the scope and spirit of the presentinvention, which is described in the accompanying claims.

What is claimed is:
 1. A smartphone comprising: a first cover layer; anLCD panel located under the first cover layer and comprising a liquidcrystal layer, a first glass layer, and a second glass layer, the liquidcrystal layer located between the first glass layer and the second glasslayer; a backlight unit located under the LCD panel and comprising anoptical film, a light source, a reflective sheet, and a second coverlayer; and a touch sensor which senses touch in a capacitive manner;wherein the backlight unit further comprises a pressure sensor and aspacer layer, the pressure sensor comprising a plurality of electrodesformed in a single layer attached on the second cover layer and spacedapart from the reflective sheet, the pressure sensor located between thereflective sheet and the second cover layer; wherein a driving signal isapplied to the touch sensor and a touch position is detected by asensing signal output from the touch sensor; wherein a magnitude of atouch pressure is detected based on a change amount of capacitance thatis output from the pressure sensor and that is changed according to adistance between the pressure sensor and an electrode located within theLCD panel; wherein the LCD panel is bent according to the touch; andwherein the change amount of the capacitance output from the pressuresensor changes as the LCD panel bends.
 2. The smartphone of claim 1wherein the electrode located within the LCD panel is composed of ITO.3. The smartphone of claim 1 wherein the electrode located within theLCD panel is a common electrode within the LCD panel.
 4. The smartphoneof claim 1 wherein the touch sensor comprises a plurality of driveelectrodes and a plurality of receiving electrodes, and at least one ofthe drive electrodes and the receiving electrodes of the touch sensorare located between the first glass layer and the second glass layer. 5.The smartphone of claim 1: wherein the LCD panel further comprises afirst polarizer layer and a second polarizer layer between which thefirst glass layer, the liquid crystal layer, and the second glass layerare placed; and wherein the touch sensor is partially located betweenthe first glass layer and the first polarizer layer.
 6. The smartphoneof claim 1 further comprising an air gap between the LCD panel and theoptical film.
 7. The smartphone of claim 1 wherein the plurality ofelectrodes comprises a plurality of channels.
 8. The smartphone of claim2 wherein the touch sensor comprises a plurality of drive electrodes anda plurality of receiving electrodes, and at least one of the driveelectrodes and the receiving electrodes of the touch sensor are locatedbetween the first glass layer and the second glass layer.
 9. Thesmartphone of claim 3 wherein the touch sensor comprises a plurality ofdrive electrodes and a plurality of receiving electrodes, and at leastone of the drive electrodes and the receiving electrodes of the touchsensor are located between the first glass layer and the second glasslayer.
 10. The smartphone of claim 2: wherein the LCD panel furthercomprises a first polarizer layer and a second polarizer layer betweenwhich the first glass layer, the liquid crystal layer, and the secondglass layer are placed; and wherein the touch sensor is partiallylocated between the first glass layer and the first polarizer layer. 11.The smartphone of claim 3: wherein the LCD panel further comprises afirst polarizer layer and a second polarizer layer between which thefirst glass layer, the liquid crystal layer, and the second glass layerare placed; and wherein the touch sensor is partially located betweenthe first glass layer and the first polarizer layer.
 12. The smartphoneof claim 2 further comprising an air gap between the LCD panel and theoptical film.
 13. The smartphone of claim 3 further comprising an airgap between the LCD panel and the optical film.
 14. The smartphone ofclaim 2 wherein the plurality of electrodes comprises a plurality ofchannels.
 15. The smartphone of claim 3 wherein the plurality ofelectrodes comprises a plurality of channels.